Patent Literatures 1 and 2 indicate refrigerant evaporators. The refrigerant evaporator evaporates a refrigerant flowing inside by absorbing heat from fluid to be cooled flowing outside, e.g., air. As a result, the refrigerant evaporator functions as a heat exchanger for cooling which cools the fluid to be cooled. Disclosed refrigerant evaporators have a first evaporative portion and a second evaporating portion which are arranged on an upstream side and a downstream side with respect to a flowing direction of the fluid in a series manner. Each evaporating portion has a core part configured by stacking a plurality of tubes, and a pair of tank parts connected to the both ends of the plurality of tubes. The core part of the first evaporating portion is partitioned in a width direction, i.e., in a right-and-left direction. In addition, the core part of the second evaporating portion is also partitioned in the width direction, i.e., the right-and-left direction.
The refrigerant evaporators disclosed in Patent Literatures 1 and 2 has an interchange part which is disposed in a communicating portion for flowing the refrigerant from the downstream first evaporating portion to the upstream second evaporating portion and interchanges the refrigerant in the right-and-left direction. The interchange part is provided by two communicating portions. One communicating portion leads the refrigerant flowing out from one side part, e.g., a right side part, of the first evaporating portion to the other side part, e.g., a left side part, of the second evaporating portion. In addition, the other one communicating portion leads the refrigerant flowing out from the other side part, e.g., a left side part, of the first evaporating portion, to the one side part, e.g., a right side part, of the second evaporating portion. The interchange part may also be called as a cross-flow passage. This structure is effective to suppress unevenness of a temperature distribution in the refrigerant evaporator. This structure is also effective to suppress the unevenness of a temperature distribution of external fluid.
In the refrigerant evaporator disclosed in Patent Literature 1, it is configured to interchange the refrigerant flow in a width direction, i.e., in the right-and-left direction, of the core part, when the refrigerant passed through the core part of the first evaporating portion to the core part of the second evaporating portion through one side tank part of the evaporating portions and a pair of communicating portions which connect the tank parts. That is, the refrigerant evaporator is configured to make the refrigerant flowing in one side of the core part of the first evaporating portion in the width direction flows into the other side of the core part of the second evaporating portion in the width direction by using one communicating portion, and to make the refrigerant flowing in the other side of the core part of the first evaporating portion in the width direction flows into the one side of the core part of the second evaporating portion in the width direction by using one communicating portion among a pair of communicating portions.